A portable biosensor system provided with a measuring device having a calculating unit and a sensor chip detachable from the measuring device is used for measuring an analyte concentration, for example a blood glucose concentration (blood glucose value) in a blood sample. The analyte concentration is calculated by an optical method or an electrochemical method based on an amount of a reductant or an oxidant produced by an oxygen cycling reaction mediated by an oxidoreductase that uses the analyte as a substrate. The speed of the oxygen cycling reaction depends on the temperature that promotes the reaction (reaction temperature). As a result, the concentration of the analyte is preferably corrected with reference to the reaction temperature.
The reaction temperature for example is measured by a temperature sensor disposed in the measuring device (Patent Literature 1). However, in the biosensor system according to Patent Literature 1, the inner portion temperature of the measuring device is measured, and therefore the measured reaction temperature does not accurately reflect the temperature of the blood sample. As a result, an error may result in the measurement of the analyte concentration.
Patent Literature 2-4 disclose a biosensor system for improving the measurement accuracy of the reaction temperature. The biosensor system in Patent Literature 2 and 3 includes a heat conduction member in proximity to the blood sample retention unit of the sensor chip, and detects the temperature of the blood sample transmitted through the heat conduction member with a temperature sensor disposed in the measuring device. Since the biosensor system in Patent Literature 2 and 3 includes a resin plate disposed between the heat conduction member and the blood sample retention unit, the heat conduction member does not come into contact with the blood sample. The biosensor system in Patent Literature 4 includes a temperature sensor and a heat conduction member disposed in a mounting unit of the measuring device for mounting of the sensor chip, and therefore transmits the temperature of the blood sample to the temperature sensor through the heat conduction member.